Representational forms of data and data structures are often displayed to a user via a user interface. The forms of the data are “representational” in the sense that data is typically stored in various forms of memory as one or more series of binary signals in electrical and magnetic storage devices, but may be translated into characters (representations), often alphanumeric, comprehensible by users interacting with them. A data structure is a particular way of organizing and storing data in a computer so that it may be used efficiently. Common data structures include arrays, linked lists, tables (e.g., hash-tables), heaps, trees, stacks, and queues.
For example, a database typically takes advantage of a tree structure as databases are often administered in a hierarchical manner. Such a tree structure contains a number of (dominant) items, and each item may have an arbitrary number of (subordinate) items. Several interrelated items will typically be grouped under a single dominant item. Subordinate items may be dominant to and contain subordinate items of their own.
Data entries may be presented in the logical organization of a data structure, e.g., a visual list, a tree structure, a table, etc. When displayed in a user interface, large data structure representations can easily occupy a space spanning beyond the limits of the user interface, making them hard to visualize and even harder to manipulate via the user interface. A scrolling window can be used to show all the data entries but may be computationally expensive. Alternatively, at the end of the visible data entries within a user interface, a summation line or marker may be included indicating an amount of remaining non-visible or “hidden” data entries. Such a summation line may be expandable to display additional, previously non-visible, data entries that are often then subject to a scrolling window or visible in a separate view.